1. Field of the Invention
The present invention relates to a manipulator system operated by an operator, and more particularly, to a manipulator system which enables a person to perform manual operations at a point spaced from a work site which presents an unendurable environment to him, such as space.
2. Description of the Prior Art
Control of the complicated operations of the conventional manipulators requires the skill or the ability of an operator. In the case of a master slave type manipulator, since the configuration of a master arm is the same as or analogous to that of a slave arm, the master arm may take a form which is unsuited to control by the operator, may be so large as to inhibit operation by the operator, or may be constructed such that it cannot perform delicate manual operations.
With the availability of sophisticated electronic hardware and system software during the past decade, computers are used to achieve the sophisticated control of manipulators or robots. Examples of such a manipulator system include the one described from page 40 to page 45 in IECON' 84. In this manipulator system, a master arm and a slave arm have different configurations, and high-speed coordinate transformation operations are performed by a computer to accomplish one-to-on correspondence between the motions of the master arm and those of the slave arm.
This master slave manipulator system including the arms having different configurations has advantages in that the operative range of the slave arm can be expanded, and in that the master arm can be constructed such that it matches the body of the operator, enabling the operationality of the master arm, i.e., the ease with which the master arm can be used, to be improved.
Thus, utilization of the computer in the manipulator system enables the operationality and the workability, i.e., the ability with which the system can perform work, of the system to be improved. Computers may be utilized in the manipulator system more effectively to improve the operationality and the workability of the system by examining the master/slave arm mechanism. Such research is described from page 3 to page 13 and from page 14 to page 21 in the Journal of the Japan Robots Association No. 5 Vol. 4, published in October, 1986.
However, in the above-described research, the follow-up property and the calculation time have been examined, but the ease with which the master/slave arms can be operated has not been sufficiently studied.
A master arm structure which is improved to improve the ease with which it can be operated has been made public in the literature of the Japan Robots Association. However, this technique gives no consideration to the operationality of the overall master slave manipulator system including the master arm.
Japanese Unexamined Patent Publication No. 63-22283 discloses a master arm structure which is designed to improve the ability with which manual operations can be done by the master arm. U.S. Pat. application Ser. No. 363,071 discloses a manipulator wrist with three axes intersecting at right angles.
In order to improve the ease with which the master arm of the manipulator can be operated, the orientation of a person's eyes and hands, the angle through which a wrist is bent, twisted or inclined toward or away from the person's body, and degrees of freedom and range of the motions of a arm have to be taken into consideration when the structure of a master arm is to be determined.
The structure of a slave arm is restricted by the contents of work to be done, its folding ability, and its operating range.
Singular points have also to be taken into consideration when the operationality and the workability are to be improved.
With these factors as well as the control system taken into consideration, the operationality and the workability of an integrated master slave manipulator system may be improved.
The master arm and the slave arm have both different portions and similar portions in their structures because the structure of the master arm is determined by the build of a man and the structure of the slave arm is determined by its application.
When a manipulator system incorporating a master arm and a slave arm having different dimensions and configurations is used, the motions of the master arm and those of the slave arm must be in one-to-one correspondence, requiring the provision of a coordinate transforming unit. When a small master arm is controlled to move a large slave arm in a large motion, the scale of the operation has to be enlarged. Furthermore, when the small master arm is controlled to move the large slave arm to do detailed work in various portions of the large operation range of the slave arm, the scale of the operation has to be reduced or the starting point of the operation has to be shifted.
These enlargements and reductions in the scale and shift of the starting point require a coordinate transformation supplementing unit for further transforming the data of the coordinate transforming unit. In the manipulator system incorporating a master arm and a slave arm both of which have six degrees of motion, when the rotational center of one axis of motion coincides with that of another axis of motion, control of the system becomes impossible. Such a problem involving the singular point may be solved by improving the structure of the master arm and by improving the control system of the slave arm.
The present invention is intended to solve the problems involving the ease with which the system can be operated from the viewpoint of the overall master slave manipulator system.